Releasable thread clamp



July 23, 1968 T. FRANSEN 3,393,712

RELEASABLE THREAD CLAMP Filed April 11, 1966 United States Patent Ofice 3,393,712 Patented July 23, 1968 3,393,712 RELEASABLE THREAD CLAMP Theodorus Fransen, Deurne, Netherlands, assignor to N.V. Machinefabriek L. te Strake Deurne, North Brabant, Netherlands, a Dutch company Filed Apr. 11, 1966, Ser. No. 541,618 Claims priority, application Netherlands, Apr. 15, 1965,

6504919 5 Claims. (Cl. 139-122) ABSTRACT OF THE DISCLOSURE A releasable clamp for clamping a thread in textile machinery, comprising a pair of opposed clamping members, each having a thread-clamping surface, at least one of the clamping members being retractable from its threadclamping position to release the clamp, and a pair of abutments, one for each clamping member, each of which abutments is adjacent to the thread-clamping surface of its clamping member, and extends beyond such surface toward the thread when said one clamping member is retracted, so as to bend the thread away from the threadclamping surface in order to cause the thread to pull free from the thread-clamping surface by tension applied to the thread.

Background of the invention The invention relates to a releasable clamp to be used in conjunction with a thread. Said clamp is provided with one or more stamps having a clamping surface for clamping a thread running along the stamps. In textile equipment releasable thread clamps are used for holding a thread or to prevent a thread from sagging when no pull is exerted on the thread.

If a thread is to be conveyed by means of air jet action e.g. in looms in which a weft is to be blown into the shed by means of air under pressure, the thread should be immediately freed when a clamping action of a thread clamp on the thread is released.

When using thread clamps it occurs that when releasing the clamp the thread will stick to the clamping surface of a stamp as a result of the pressure, which the clamp has applied to the thread before the clamp is released. The consequence thereof is that the thread cannot be pulled away at the exact moment if the thread is to be conveyed by air under pressure.

Summary of the invention The object of the invention is to provide a releasable clamp for a thread in which the above mentioned drawback is avoided.

A releasable clamp for a thread according to the invention is characterized in that the stamps of the clamp cooperate with an abutment for the thread, which abutment projects from the clamping surface of the stamps in a direction towards the thread, when the clamp is released.

When releasing the thread the stamps of the clamp move from each other and if a thread sticks to one of said clamping surfaces the abutment will draw the thread from said clamping surface and the thread is entirely freed.

A practical embodiment according to the invention is attained in that the abutment is adapted as a wall of a passage for the thread and the stamp belonging to said wall can be retracted behind this wall when releasing the thread. It is advisable that the stamp be shaped as a core situated within the abutment.

According to the invention it is also possible that the abutment and the concerning stamp be movable together in such a manner that the direction of movement of said abutment is opposed to the direction of movement of said stamp. In this case it is advisable that the abutment be shaped as a core positioned within the stamp.

Some embodiments according to the invention will be described with reference to the accompanying drawing.

Brief description of the drawing FIG. 1 is a diagrammatical side view of a known clamp for a thread;

FIG. 2 is a side view partially in section of the clamping part of a releasable thread clamp according to the invention showing a first embodiment in which stamps of the thread clamp are just opened for releasing the clamping action on a thread;

FIG. 3 is the same view as that of FIG. 2 in which the thread clamp is entirely opened;

FIG. 4 is a vertical section through a thread clamp according to the invention in a second embodiment, in which the clamp is closed to clamp a thread;

FIG. 5 is the same section as that of FIG. 4, in which the thread clamp is opened and the thread is released, and

FIG. 6 is a cross section of a thread clamp according to the invention in a third embodiment.

Description of the preferred embodiments When a thread is clamped between two opposed clamping members or stamps 1a and 1b it can happen that the thread 2 will stick to the clamping face of one of the stamps after the stamps 1a and 1b are removed from each other as indicated in FIG. 1.

In order to eliminate such sticking of the thread the stamps 1a and 1b are provided with an abutment 3a, 3b respectively. The abutments 3a and 3b are adapted as a sleeve around the stamps 1a and 1b and the endfaces 4 of the abutments 3a and 3b are directed towards the thread 2 to confine the passage for the thread.

When new the thread 2 sticks e.g. to the stamp 1a as a result of the clamping force exerted upon the thread by the stamps this thread will be released from the clamping face of the stamp In as the abutment 3a extends over this clamping surface of the stamp 1a in a direction towards the thread when the thread clamp is opened, so as to bend the thread away from the clamping surface of the stamp 1a in order to cause the thread to pull free from the clamping surface by the tension applied to the thread. This situation is indicated in FIG. 3. The thread becomes entirely free, because the force applied to the thread when releasing the thread from the stamp 1a is insufficient to stick the thread further e.g. at the end face 4 of the abutment 3a.

In the embodiment of a thread clamp according to the invention as indicated in FIGS. 2 and 3 the stamps 1a and 1b are adapted as cores which are movable within the abutments 3a and 3b, respectively. The stamps 1a and 1b are driven or controlled by means of a mechanism adapted for this purpose as known per se in clamps for a thread. A typical mechanism for driving and controlling a pair'of stamps is shown in FIG. 5. In a thread clamp according to FIGS. 4 and 5 the stamps 5a and 5b which can be considered as jaws of a clamp are formed as hollow cylindrical members.

The clamping faces 6 of the stamps 5a and 5b are obtained by bending a rim of said stamps towards their centre. The axially bent rim is adapted to enclose the movable abutments 7a and 7b within the stamps 5a and 5b. The abutments 7a and 7b are provided with a shoulder 8 which remains behind the bent rim, which bent rim is adapted to form a clamping face 6 of each stamp.

Owing to this the abutments 7a and 7b cannot fall out of the stamps. The reduced part 9 of the abutment 7a will project through the central opening in the clamping face 6 by the weight of the abutment 7a when the stamps a and 5b are removed from each other as indicated in FIG. 5. The abutment 7b is supported by a spring owing to which, the reduced part 9 of the abutment 7 projects also through the central opening in the clamping face 6 of the stamp 5b, when the clamp is released from the thread. The pressure exerted by the spring 10 and the abutment 7b onto the thread 2 is considerably less than the pressure which is exerted on the thread by the stamp 5b when the thread is clamped between the stamps. When the thread 2 sticks to the clamping face 6 of the stamp 5a the weight of the abutment 7a will release the thread from this clamping face. If, however, the thread sticks to the clamping face 6 of the stamp 5b, the abutment 7b will release the thread from this clamping face 6 by the action of the spring 10.

Referring to the embodiment of FIG. 6 only one driven stamp 11 is provided, which stamp 11 cooperates with a clamping face 12. The clamping face 12 is the end face of a hood shaped clamping member 14, which can be displaced in axial direction within a housing 13. The clamping face 12 is resilient, because the hood shaped member 14 is supported by a spring 15. The clamping face 12 is lowered with respect to the edges 16 of the housing, which edges 16 form the boundaries of the passage for the thread. The edges 16 act as an abutment to release the thread from the clamping face 12 when the thread tends to stick thereon after release of the pressure of the stamp 11.

A notch 18 is situated in the clamping face 17 of the stamp 11 and a pin 19 which is secured at both ends in the housing 13 fits into this notch. When now the stamp 11 moves into its clamping position the pin 19 enters the notch 18. When the stamp 11 moves from its clamping position to the position indicated in FIG. 6 the pin 19 will release the thread 2 from the clamping face 17, when the thread tends to stick against the clamping face 17.

In contrast to the embodiments according to FIGS. 4 and 5 in which the abutments 7a and 7b are movable together with the stamps 5a and 5b, respectively, in the embodiment of FIG. 6 the abutments in the form of the pin 19 and in the form of the edges 16 are stationary.

If the thread is tensioned upward on both sides of the thread clamp of FIG. 6 only the provision of the pin 19 is necessary and the edges 16 need not be used as an abutment for the clamping face 12.

FIG. 5 shows a typical mechanism for driving and controlling a stamp. The upper end of the stamp 5a is provided with a bore 20a in which is rotatably mounted a pin 21a which extends in an eccentric position from the end of a shaft 22a. In order to drive and control the stamp 5a, the shaft 22a is rotated by means of bevel gears 23a.

The stamp 5b is driven and controlled by a mechanism similar to that just described, which includes a shaft 22b, driven by bevel gears 23b, from the end of which extends an eccentric pin 21b that is rotatable in the bore 20b of the stamp 5b. In order to operate the two stamps 5a and 5b in synchronism, the bevel gears 23a and 23b Which Operate the two stamps may be driven by a common shaft as indicated in FIG. 5.

I claim:

1. A releasable clamp for clamping a thread in textile machinery, comprising a pair of opposed clamping members, each having a thread-clamping surface, at least one of the clamping members being retractable from its threadclamping position to release the clamp, wherein the improvement comprises a pair of abutments, one for each clamping member, each of which abutments is adjacent to the thread-clamping surface of its clamping member, and extends beyond such surface toward the thread when said one clamping member is retracted, so as to bend the thread away from the thread-clamping surface in order to cause the thread to pull free from the thread-clamping surface by tension applied to the thread.

2. A releasable clamp according to claim 1 wherein an abutment is located outside of the thread-clamping surface of a retractable clamping member, in alignment with the path of the thread passing over such surface.

3. A releasable clamp according to claim 1 wherein an abutment surrounds the thread-clamping surface of its clamping member.

4. A releasable clamp according to claim 1 wherein an abutment is movable relative to a retractable clamping member in a direction opposed to the retracting movement of the clamping member, so as to extend beyond the thread-clamping surface of the clamping member toward the thread when the clamping member is retracted.

5. A releasable clamp according to claim 1 wherein an abutment is surrounded by the thread-clamping surface of its clamping member.

References Cited UNITED STATES PATENTS 466,088 12/1891 Bauer 242-149 591,044 10/1897 Keith 242l49 1,042,756 10/1912 Beeman et al 242l49 2,209,839 7/1940 Long 242l49 X 2,668,560 2/1954 Svaty 139-127 2,624,370 1/1953 Flamand 139-127 3,269,426 8/1966 Llado 139-122 FOREIGN PATENTS 593,034 5/1959 Italy.

1,336,177 7/1963 France.

MERVIN STEIN, Primary Examiner.

JAMES KEE CHI, Assistant Examiner. 

